Projection-type display device and software program

ABSTRACT

A projection surface on which a predetermined projection image is projected is provided; a writing surface on which an image can be drawn directly in a superimposing manner with a projection image displayed on the projection surface is provided; and a photography part photographing an image drawn on the writing surface by means of an image-pickup part comprising two-dimensionally-disposed pixels is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.10/085,732 filed on Mar. 1, 2002, and in turn claims priority to JP2001-059321 filed on Mar. 2, 2001, JP 2001-255119 filed on Aug. 24,2001, and JP 2002-050541 filed on Feb. 26, 2002, the entire contents ofeach of the above-noted applications being incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a projection-type display device, and,in particular, to a projection-type display device having a novelfeature of improving a system of combining an image projected and animage drawn thereon by a user.

2. Description of the Related Art

Conventionally, generally, a projection-type display device is appliedto a projector, a media board with a display device, a personalcomputer, etc., is used as a monitor for two or more persons in ameeting, a lecture, etc., or is used as a monitor, such as in a personalcomputer used individually.

Such a projection-type display device is demanded to have a feature suchthat letters/characters, and/or pictures may be drawn on a displaydevice in a superimposing manner together with an image projected there,and, also, the thus-drawn letters/characters and/or pictures can beobtained as electronic data.

For this purpose, an art is proposed in which a position of a nibcontacted on a display screen is detected, and is traced. However, inorder to detect the position at which the nib contacts, it is necessaryto provide a special pen with the nib. Furthermore, in order toadd/erase a letter/character/picture, it is needed to appropriatelychange a screen operation mode. Thus, the whole system becomes expensiveand operation becomes complex.

Further, another art is disclosed by Japanese laid-open patentapplication No. 3-43726 in which an image drawn by a nib or the like ona display screen is scanned by a line-type photo-sensor, and, thethus-detected image is printed out. However, as the line-typephoto-sensor should have a size corresponding the size of the screen,the scanner should be larger in case the size of the screen is larger.In such a case, as the scanner mechanically scans the screen, amechanism of moving the scanner also may be of large-sized. Thus, thewhole system may become bulky. Also, as the screen is scanned by thescanner mechanically, a considerable time is required to read the wholeimage present on the screen.

According to a media board disclosed in Japanese laid-open patentapplication No. 6-347898, while an image printed on a transparent sheetis displayed on a screen, it is possible to draw/writeletters/characters/pictures thereon. Further, as a scanner scans thethus-drawn image, the scanned image can be easily printed out, as a hardcopy. However, in this art, as the scanner mechanically scans the imagepresent on the screen, the problems same as in the above-mentioned artmay occur, i.e., the whole system may become bulky.

According to a so-called optical blackboard disclosed by Japaneselaid-open patent application No. 8-160539, as a user points on a screenby a special pen, an image is projected thereon according to a locusalong which the user has moved the pen on the screen through a functionof a photo-sensing technology or a pressure-sensing technology. In thisart, as an image is displayed on the screen as a result of the usermoving the special pen on the screen and then the movement beingdetected by the system, the relatively complex system is needed merelyfor drawing an image on the screen by the user, in comparison to a casewhere a user draws an image directly on a screen with ink or the like byusing a common ink-used pen as in a common whiteboard.

According to a media board disclosed by Japanese laid-open patentapplication No. 10-297166, an image drawn on a screen is readelectronically, the read image data is combined with another image beingprojected on the screen. However, no specific configuration of how toread a drawn image is disclosed in the publication.

SUMMARY OF THE INVENTION

The present invention is directed to the above-mentioned problems, and,an object of the present invention is to provide a projection-typedisplay device in which, as a writing surface on which a userdraws/writes an image is made approximately coincident with an imageprojection surface, operativity is improved, the whole system issimplified, and, also, the cost needed can be effectively reduced.

Further, according to the present invention, a software program forcontrolling the above-mentioned projection-type display device from anexternal personal computer etc., is provided. Thereby, it is possible toprovide the projection-type display device less costly.

According to the present invention, a projection surface is provided onwhich a predetermined projection image is displayed through projection;a writing surface is provided on which an image can be drawn directly ina superimposing manner with the projection image displayed on theprojection surface; and a photography part is provided for photographingthe image drawn on the writing surface by means of an image-pickup partcomprising two-dimensionally-disposed pixels.

Thereby, as a user can draw any image such asletters/characters/pictures on the writing surface in a manner same asin a case of a common whiteboard or blackboard, and, thus, auser-friendly system can be provided. Further, as it is possible to drawan image on the writing surface superimposing manner with the projectionimage displayed on the projection surface, the drawn image andprojection image are combined properly on the sight of the user.Accordingly, a high-operative system can be provided.

Further, as the drawn image is photographed through an image-pickup parthaving two-dimensionally disposed pixels (such as a so-called digitalstill camera), it is easy to read the drawn image rapidly, and, also, itis not necessary to prepare a large-sized configuration to read even alarge-sized image drawn on a screen. Accordingly, the whole system canbe effectively miniaturized, and, thus, it becomes less costly.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and further features of the present invention will becomemore apparent from the following detailed description when read inconjunction with the following accompanying drawings:

FIG. 1 shows an outline view of a projection-type display device in eachembodiment of the present invention;

FIGS. 2 and 3 show an internal configuration of the projection-typedisplay device shown in FIG. 1;

FIG. 4 shows a block diagram of a projection-type display device in afirst embodiment of the present invention;

FIG. 5 shows a block diagram of a processing control part shown in FIG.4;

FIG. 6 illustrates operations of producing a user-drawn image and acombined image according to the present invention;

FIGS. 7A and 7B illustrate two types of internal arrangement of theprojection-type display device in the first embodiment of the presentinvention;

FIG. 8 shows a flow chart illustrating operation of the projection-typedisplay device in the first embodiment of the present invention;

FIG. 9 shows a block diagram of a projection-type display device and apersonal computer according to a second embodiment of the presentinvention;

FIGS. 10A and 10B illustrate a projection-type display device in a thirdembodiment of the present invention;

FIG. 11 shows a block diagram of the projection-type display device inthe third embodiment of the present invention;

FIG. 12 shows a flow chart illustrating operation of the projection-typedisplay device in the third embodiment of the present invention;

FIG. 13 shows a block diagram of a projection-type display device and apersonal computer according to a fourth embodiment of the presentinvention;

FIG. 14 illustrates a CCD and a piezoelectric device according to afifth embodiment of the present invention;

FIG. 15 shows a block diagram of the projection-type display device inthe fifth embodiment of the present invention;

FIG. 16 shows a flow chart illustrating operation of the projection-typedisplay device in the fifth embodiment of the present invention;

FIG. 17 shows a block diagram of a projection-type display device and apersonal computer according to a sixth embodiment of the presentinvention;

FIGS. 18 and 19 show an internal view of a projection-type displaydevice in a seventh embodiment of the present invention;

FIG. 20 illustrates divided photography areas on a writing field of theprojection-type display device in the seventh embodiment of the presentinvention;

FIG. 21 shows a flow chart illustrating operation of the projection-typedisplay device in the seventh embodiment of the present invention;

FIGS. 22 and 23 show an internal view of a projection-type displaydevice in an eighth embodiment of the present invention;

FIG. 24 shows a perspective view of a photography part used in theprojection-type display device in the eighth embodiment;

FIG. 25 shows a block diagram of the projection-type display deviceaccording to the eighth embodiment of the present invention;

FIG. 26 shows an internal view of a projection-type display device in aninth embodiment of the present invention;

FIGS. 27A and 27B show an internal view of a projection-type displaydevice in a tenth embodiment of the present invention;

FIGS. 28A and 28B show an internal view of a projection-type displaydevice in an eleventh embodiment of the present invention;

FIG. 29 shows an internal view of a projection-type display device in atwelfth embodiment of the present invention;

FIG. 30 shows a dispersion sheet and a winding roller according to thetwelfth embodiment of the present invention shown in FIG. 29;

FIG. 31 shows an internal view of a projection-type display device in athirteenth embodiment of the present invention;

FIGS. 32A, 32B and 32C show a dispersion sheet and winding rollersaccording to the thirteenth embodiment of the present invention shown inFIG. 31; and

FIGS. 33A, 33B and 33C show a configuration of a support board, awriting field and a transparent screen according to a fourteenthembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described.However, respective components, specific types thereof, combinations,shapes, relative spatial arrangements, and so forth thereof which willbe described are merely examples, and the present invention is notlimited thereto. Further, for the same components, the same referencenumerals will be given throughout the respective embodiments.

FIG. 1 shows an appearance of a projection-type display device in afirst embodiment of the present invention.

In this projection-type display device, a user can write, by using a pen2 for writing, letters/characters, images, etc. on a writing field 1. Asfor the pen 2 for writing, a generally sold marker used for writing ontoa whiteboard, such as a common pen employing alcoholic ink, may be used.Further, the writing field (sheet) 1 is made of material such that animage projected on a transparent screen 6 (see FIG. 2) provided on theside opposite to the user side can be sufficiently transmitted thereby.Thereby, the user can view an image projected on the transparent screen6 by a projector 4 (see FIG. 2) through the writing field 1. Inaddition, such a treatment is made on a surface of the writing field 1on which writing is made by the user that an image drawn thereon by inkmay be easily erased by a cloth or the like, as in a common whiteboard.

The projection-type display device is enclosed by a housing 3 such that,as shown in FIG. 3, particularly a zone through which a light beam 41passes from the projector 4 to the screen 6 is enclosed thereby.Further, switches 11 which provide functions as a user interface areprovided on the housing 3, and, thereby, the user can freely controlvarious conditions in the projector 4 and a CCD (Charge Coupled Device)camera 7, such as image display conditions, image-pickup conditions, andso forth.

FIG. 2 shows an inside rear view of the projection-type display devicein the first embodiment while FIG. 3 shows an inside side view of thesame.

The projector 4 projects an image onto the transparent screen 6 througha reflective mirror 5. The transparent screen 6 is provided inside withrespect to the writing field 1. In this configuration, since the field 1is transparent, the user can view the projected image through thewriting field 1 from the outside.

Further, an image written/drawn onto the writing field 1 by the user canalso be viewed from the inside of this projection-type display devicethrough the transparent writing field 1 and the transparent screen 6.Therefore, the CCD camera 7 provided inside of the display device cantake a picture of the image written/drawn on the writing field 1. In thefirst embodiment, the CCD camera 7 takes a picture of an image writtenon the writing field 1 also through the reflective mirror 5.

Furthermore, by a processing control part 8 (see FIG. 4) provided insideof the display device, predetermined processing is performed, and animage electronically taken in by the CCD camera 7 is output to theoutside through an input-and-output part 9 (see FIG. 4) also provided inthe display device.

In addition, the projector 4, reflective mirror 5, and transparentscreen 6 mainly act as a projection part, while the CCD camera 7,writing field 1 and reflective mirror 5 mainly act as a photographypart. Further, the switches 11 mainly act as a mode selection part.

According to a basic feature of the projection-type display devicedescribed above, this display device is superior in terms of userinterface. With the same feeling as in a common blackboard orwhiteboard, the user can draw letters/characters, line drawings, etc.onto the writing field 1. Further, the user can change photography(picture taking) processing modes, described later, easily.

Further, according to the first embodiment, preferably, an imageprojected onto the transparent screen 6 and an image taken in from thewriting field 1 can be used independently. For this purpose, preferably,the projection-type display device is configured such that the imageprojected and the image taken in are taken independently. Furthermore,preferably, the surface on which an image is projected (transparentscreen 6) and a surface on which an image is drawn (writing field 1) aremade approximately coincident. Thereby, a taken-in drawn image can beeasily superimposed on a projected image through the sight of the user.Thereby, the projection-type display device excellent in operativity andfunctionality can be provided.

With reference to FIG. 4, a block configuration of the projection-typedisplay device in the first embodiment will now be described in detail.

In FIG. 4, the processing control part 8 performs control of the CCDcamera 7 and projector 4 based on signals from the switches 11.Furthermore, the processing control part 8 executes a software programread from a storage part 10 with using a work area in the storage part10 appropriately, and also executes a function of extracting an imagedrawn by the user from an image taken in through the CCD camera 7 asshown in FIG. 5.

Further, the processing control part 8 produces an image (combinedimage) in combination of an image displayed onto the projector 4 and animage (user-drawn image) drawn by the user and taken in by the CCDcamera 7. Furthermore, the processing control part 8 also controlsprocessing of storing the user-drawn image and the above-mentionedcombined image in the storage part 10, and processing of outputting themto the outside through the input-and-output part 9.

The input-and-output part 9 performs processing of inputting, into theinternal processing control part 8 and into the internal projector 4,image signals outputted from an external personal computer etc., andprocessing of outputting the user-drawn image and combined image outputfrom the processing control part 8 to the outside. In addition, thisinput-and-output part 9 includes I/O interfaces, such as a USB(Universal Serial Bus) interface, an IEEE1394 interface, and a SCSI(Small Computer System Interface), and/or includes an interface with avideo card in an external apparatus, such as a PC.

The switches 11 are used for controlling ON/OFF of the projector 4,input of user's instructions for taking a picture of user-drawn image bythe CCD camera 7, and selection between two types of photographyprocessing modes.

These two types of photography processing modes will now be described.The first photography processing mode is a mode of operation forextracting and acquiring only the above-mentioned user-drawn image, anda second photography processing mode is a mode of operation foracquiring the above-mentioned combined image in which the user-drawnimage and projection image are combined. These two photographyprocessing modes are executed as a result of the processing control part8 reads a predetermined software program from the storage part 10, asshown in FIG. 5.

As shown in FIG. 5, the processing control part 8 includes an imagereversal part 81 which reverses right and left of an image of an imagesignal input from the CCD camera 7, a user-drawn extraction part 82which extracts a user-drawn image from the thus-reversed image, and animage combining 83 which combines the user-drawn image with a projectionimage. Further, in this configuration, the image signal provided by theuser-drawn extraction part 82 or the image combining part 83 is storedby the storage part 10, is input into the projector 4 through theprocessing control part 8, or is output to an external apparatus throughthe input-and-output part 9.

With reference to FIG. 6, the operation according to the firstphotography processing mode will now be described. When the firstphotography processing mode is selected through the switches 11 by auser, the processing control part 8 causes the CCD camera 7 to take apicture of the writing field 1. Thereby, a photographed image I1 inwhich right and left are reversed as shown in FIG. 6 is acquired as aresult of the picture was taken through the reflective mirror 5 shown inFIG. 3. Then, the processing control part 8 provides a reversal image I2by reversing the right and left of the photographed image I1 through theimage reversal part 81.

Furthermore, the processing control part 8 causes the image extractionpart 82 to extract a user-drawn image I4 from the reversal image I2.This extraction is achieved as a result of the reversal image I2 havinga reference image I3 previously taken at a state in which nothing isdrawn in the writing field 1 and then reversed between right and leftthereof subtracted therefrom. Thereby, any images, other than theuser-drawn image currently drawn by user, such as cracks or the like ofthe transparent screen 6, are removed. Then, the user-drawn image I4 isstored by the storage part 10, for example, or is output to the externalapparatus through the input-and-output part 9.

Similarly operation in the second photography processing mode will nowbe described with reference to FIG. 6. When the second photographyprocessing mode is selected through the switches 11 by the user, theprocessing control part 8 extracts the user-drawn image I4 from thephotographed image I1 obtained through the CCD camera 7, as in the caseof the first photography mode. After the user-drawn image I4 is storedby the storage part 10 temporarily, it is input into the image combiningpart 83. Then, a projection image I5 currently stored in the storagepart 10 is also input into the image combining part 83. Then, the imagecombining part 83 combines the user-drawn image I4 and the projectionimage I5 together, and outputs the combined image I6.

As for the user-drawn image I4 and the projection image I5,correspondence therebetween is made by the processing control part 8.That is, the projection image projected when the user-drawn image istaken by the CCD camera 7 in response to the operation made onto theswitches 11 is made to have a correspondence to this user-drawn image.For this purpose, the processing control part 8 stores the projectionimage I5 together with the user-drawn image I4 in a manner of makingcorrespondence therebetween into the storage part 10. Thereby, it ispossible to take these images together easily in future. Further, thecombined image I6 is stored by the storage part 10, for example, or isoutput to the external apparatus through the input-and-output part 9.

Further, since the projector 4 and CCD camera 7 uses the approximatelysame surface (the writing field 1 and transparent screen 6), as shown inFIG. 7A, it is easy to combine the user-drawn image I4 obtained from thephotographed image I1 with the projection image I5 by making the opticalaxis of the CCD camera 7 coincident with a center axis 60 of the writingfield 1, the center axis 60 being perpendicular to the writing field 1.

However, in the example shown in FIG. 7A, for the sake of simplificationof illustration, the reflective mirror 5 is omitted. In case the CCDcamera 7 is disposed on the center axis 60 of the writing field 6 asshown in the figure, it is necessary to make the optical axis of theprojector 4 to be inclined as shown in FIG. 7A. Such inclination of theoptical axis can be achieved by using a well-known function of a commonprojector.

Further, in case where the projector 4 is disposed on the center axis 60of the writing field 1 as shown in FIG. 7B, although it is not necessaryto incline the optical axis of the projector 4 as mentioned above, it isnecessary to perform tilt correction on a photographed image acquired bythe CCD camera 7. Such a tilt correction can be performed according to awell-known common way, and, in this embodiment, the processing controlpart 8 performs tilt correction on the photographed image I1.

Furthermore, in the embodiment, projection of an image by the projector4 may be interrupted during the user-drawn image is pick up by the CCDcamera 7. Thereby, it can be prevented that the projection image becomesobstructive to the photography of the user-drawn image, and, thereby,the user-drawn image cannot be extracted properly. Further, in additionto this, the photographed image which also contains the projection imagemay be acquired by the CCD camera 7, and, then, the projection image maybe subtracted from the photographed image (reversal image).

The storage part 10 mainly includes a recording part, and theinput-and-output part 9 mainly includes an input part and an outputpart. The image projected by the projector 4 and the image photographedby the CCD camera 7 may be appropriately processed by an externalpersonal computer, or the like. For this purpose, the storage part 10which once stores the image and the input-and-output part 9 whichtransmits the data to the external personal computer are needed.

Further, the image projected by the projector 4 may be of image dataprocessed in by the external apparatus, or the photographed projectionimage itself. Therefore, the input-and-output part 9 is also needed.Thereby, a selected image can be recorded in the above-mentioned storagepart 10 or it can be transmitted to the external apparatus through theabove-mentioned input-and-output part 9, and, thus, it becomes easier toperform image data processing by using the external processingapparatus.

Operation of the processing control part 8 in the first embodiment willnow be described with reference to FIG. 8. In response to a signalcoming from the switches 11 indicating photography (Yes of a step S101),the processing control part 8 sends instructions such that an image onthe writing field 1 be taken by the CCD camera 7 (in a step S102), andthen, the processing control part 8 receives a photographed imagetherefrom (in a step S103). At this time, the light source in theprojector 4 may be turned off, as mentioned above.

Then, the processing control part 8 produces the user-drawn image I4 orcombined image I6 according to the process shown in FIG. 6 (in a stepS104). The user-drawn image or combined image thus produced is stored bythe storage part 10, or is output to the external apparatus through theinput-and-output part 9.

Thereby, the projection-type display device which can acquire easilyinformation input through handwriting/drawing by the user as imageinformation.

In the above-described first embodiment, processing such as control ofthe projector 4, CCD camera 7, switches 11, reversal of a photographedimage obtained by the CCD camera 7, image extraction, image combining,etc. is performed by the processing control part 8 provided inside ofthe projection-type display device. According to a second embodiment ofthe present invention, as will now be described, this processing isperformed by an external apparatus, such as a personal computer,instead.

According to the second embodiment, as shown in FIG. 9, the projector 4,CCD camera 7 and switches 11 are connected to a personal computer 108provided inside or outside of a projection-type display device as shownin FIG. 9. USB, IEEE1394, SCSI, etc. are applied as the interface forconnecting these respective components. Driver software (a CCD cameradriver 1081, a projector driver 1082, and a switch driver 1083) forcontrolling the CCD camera 7, projector 4, and switches 11 is installedin the personal computer 108, and, thereby, control of each component,and input and output of various instructions and/or datatherefrom/thereto are performed.

Thus, according to the second embodiment, the configuration of theprojection-type display device is simplified, and, also, a predeterminedsoftware provides various control processing needed. Thereby, theprojection-type display device can be provided at low cost.

Since the other configurations and operations are the same as those ofthe first embodiment, duplicated description is omitted.

According to the second embodiment, the function of the processingcontrol part 8 in the first embodiment is achieved directly by the CPU(central processing unit) included in the personal computer 108.

A projection-type display device in a third embodiment of the presentinvention will now be described. FIGS. 10A and 10B illustrate an innerstructure of the projection-type display device in the third embodiment.

According to the above-mentioned first embodiment, when the light sourcein the projector 4 is turned off in order to prevent floodlighting ofthe projector 4 from being applied in photographing a user-drawn imageformed on the writing field 1 by the CCD camera 7, a considerable timeis taken for again starting up the floodlighting for image projection bythe projector 4, and, also, the life of the power supply thereof may beshortened through repetitive turning on/off thereof. In order to avoidsuch a situation, as shown in FIGS. 10A and 10B, a light-blocking plate21 for blocking the light beam emitted from the projector 4 is providedin the third embodiment of the present invention.

In the configuration of the third embodiment, the light-blocking plate21 is removed and thus, the transparent screen 6 can have an imageprojected thereunto from the projector 4 at a time of image projection,as shown in FIG. 10A. On the other hand, at a time of photography of auser-drawn image formed on the writing field 1, the light-blocking plate21 is placed in front of the projector 4, and thereby, the light beamemitted by the projector 7 is prevented from reaching the transparentscreen 6, as shown in FIG. 10B. Removing and inserting of thelight-blocking plate 21 mentioned above is performed by using a steppermotor 22, or the like which is driven and controlled by the processingcontrol part 8.

FIG. 11 is a block diagram showing a configuration of theprojection-type display device in the third embodiment. Thus, differentfrom the above-mentioned first embodiment, the projection-type displaydevice according to the third embodiment includes the stepper motor 22,and the processing control part 8 controls the stepper motor 22, andthus controls removing and inserting of the light-blocking plate 21appropriately from/to the front side of the projector 4

As described above, the first or second photography processing mode isthe mode in which an image which a user draws onto the writing field 1is photographed by the CCD camera 7. However, if a projection imageformed by the projector 4 is present on the transparent screen 6, theuser-drawn image formed on the writing field 1 may not be photographedclearly. This is because a halogen lamp is generally used as the lightsource of the projector 4, and, thus, it may be difficult to clearlyphotograph the user-drawn image superimposed on the projection image interms of brightness and luminous energy.

Then, it is desirable at a time of the first or second photographyprocessing mode to prevent the image from being projected by theprojector 4. Since the light beam emitted by the projector 4 is thusblocked by the light-blocking plate 21 at a time of the first or secondphotography mode according to the third embodiment, the user-drawn imageon the writing field 1 can be photographed independently and clearly.

Operation of the processing control part 8 according to the thirdembodiment will now be described with reference to FIG. 12. Theprocessing control part 8 drives the stepper motor 22 so as to make thelight-blocking plate 21 be inserted, and, thus, block the light beamemitted by the projector 4 (Step S202), when a signal is inputted fromthe switches 11 (Yes of a step S201). Then, after the light beam fromthe projector 4 is blocked, the processing control part 8 controls theCCD camera 7 so as to cause it to photograph the image on the writingfield 1 (in a step S203), and acquires the thus-photographed image (in astep S204). At this time, the light source of the projector 4 is notturned off.

Then, the processing control part 8 produces the user-drawn image orcombined image according to processing shown in FIG. 6 from thephotographed image acquired in the step S204 (in a step S205). Then, theuser-drawn image or combined image thus generated by is stored asmentioned above in the storage part 10, or is output to the externalapparatus from the input-and-output part 9.

Then, after acquiring the photographed image in the step S204, theprocessing control part 8 drives the stepper motor 22 so that thelight-blocking plate 21 may be removed and allows the projection imageto be displayed on the transparent screen 6 (in a step S206).

Thus, according to the third embodiment, since the photographed imagecan be obtained in a condition in which the light beam from theprojector 4 is prevented from reaching the transparent screen 6 withoutturning off of the light source of the projector 4, the life of theprojector 4 can be prevented from being superfluously shortened.

Since the other configurations and operations are the same as those ofthe first embodiment, duplicated description is omitted.

The above-mentioned third embodiment may also be configured by utilizinga personal computer or the like together with software programs as theabove-mentioned first embodiment is modified into the second embodiment,as in a fourth embodiment of the present invention. FIG. 13 shows ablock diagram of this fourth embodiment of the present invention. Thisblock configuration is the same as that of the second embodiment shownin FIG. 9 except that the stepper motor 22 and a stepper motor driver1084 (application software) are added. All the functions/operations ofthe fourth embodiment are the same as those of the third embodiment, andduplicated description is omitted.

A fifth embodiment of the present invention will now be described. FIG.14 illustrates a CCD 31 provided inside of the CCD camera 7.

When photographing an image present on the writing field 1 by the CCDcamera 7, the resolution poses a problem. In order to increase theresolution in photography by the CCD camera 7, according to the fifthembodiment, pixel shifting function is applied. Thereby, the writingfield 1 is photographed twice, and, at this time, the CCD 31 shown inFIG. 14 is shifted by a distance corresponding to predetermined pixels(for example, one pixel) vertically or horizontally. Thereby, theresolution along the direction in which the CCD 31 is thus shifted canbe increased double. By increasing the number of times of photographywith the pixel shift each time, i.e., by 3 times, 4 times, . . . , theresolution is increased by 3 times, 4 times, . . . , accordingly.

In the example shown in FIG. 14, when photographing the writing field 1in 2 steps with the CCD camera 7, the photography area is shifted by adistance for one pixel vertically. In order to embody a mechanism ofshifting the CCD 31 as mentioned above, a piezoelectric device drivecircuit 33 which drives a piezoelectric device 32 based on a signalgiven by the processing control part 8 may be employed for example.

The thus-obtained two pixel-shifted photographed images are input intothe processing control part 8, and are combined together. Specifically,the combined image is obtained as a result of the pixels on the twoimages are arranged alternately one by one. According to the fifthembodiment, it is possible to effectively improve the resolution of thephotographed image without increasing the pixels of the CCD 31 itself.

However, the number of pixels by which the shift is made and thedirection of the shift are not limited. For example, the writing field 1may be divided into division areas, and, each division area isphotographed by the CCD camera 7 by shifting the photography area of thecamera 7 as mentioned above. Further, a user may select whether or notsuch shift function is applied, through the switches 11.

FIG. 15 is a block diagram showing a configuration of the fifthembodiment. A different point of the projection-type display device inthe fifth embodiment from the above-mentioned third embodiment is thatthe piezoelectric device drive circuit 33 is added, the processingcontrol part 8 controls the piezoelectric device drive circuit 33, andthe CCD 31 is thereby mechanically moved by (distance corresponding to)1 pixel, as mentioned above.

Generally many electric charge accumulation type CCD elements are usedin the CCD camera 7. Many pixels are regularly arranged by unit area,and the CCD element accumulates the electric charge according toluminous energy irradiated there, and carries out photoelectrictransform. Therefore, when it shifts by 1 pixel, a photograph is takenand the image data is combined afterwards when photographing a fixedarea twice, it is possible to obtain a photograph same as that obtainedby the double recording density. According to the fifth embodiment, forthis reason, the resolution of the photographed image is improved twice.Further, by employing the piezoelectric device called a piezoelectricvibrator, it is possible to shift the CCD precisely by one pixel as thepiezoelectric device has a mono-crystal formation and vibrates at apeculiar pitch as well-known.

Operation of the processing control part 8 according to the fifthembodiment will now be described with reference to FIG. 16. Theprocessing control part 8 drives the stepper motor 22 so as to make thelight-blocking plate 21 be inserted, and, thus, block the light beamemitted by the projector 4 (Step S302), when a signal is inputted fromthe switches 11 (Yes of in a step S301). Then, after the light beam fromthe projector 4 is thus blocked, the processing control part 8 controlsthe CCD camera 7 so as to cause it to photograph the image on thewriting field 1 (in a step S303), and acquires the thus-photographedimage (in a step S304). At this time, the light source of the projector4 is not turned off.

Then, the processing control part 8 moves the CCD 31 through thepiezoelectric device drive circuit 33 by 1 pixel by means of thepiezoelectric device 32 (in a step S305), and then controls the CCDcamera 7 to take a photograph similarly (in a step S306), and acquiresthe thus-photographed image (in a step S307). Then, when the twophotographed images shifted by 1 pixel are thus acquired, the processingcontrol part 8 returns the CCD 31 to the original position by returningthe piezoelectric device 32 to the original state through thepiezoelectric device drive circuit 33 (in a step S308).

Then, the processing control part 8 combines the thus-obtained twophotographed images (in a step S309). Then, the processing control part8 produces the user-drawn image or combined image according toprocessing shown in FIG. 6 from the pixel combined image acquired in thestep S309 (in a step S310). Then, the user-drawn image or combined imagethus generated is stored as mentioned above in the storage part 10, oris output to the external apparatus from the input-and-output part 9.

Then, after acquiring the photographed image in the step S307, theprocessing control part 8 drives the stepper motor 22 so that thelight-blocking plate 21 may be removed (in a step S311).

In addition, the user-drawn image or the combined image generated bythis is stored as mentioned above in the storage part 10, or is outputto the external apparatus from the input-and-output part 9.

Accordingly, it is possible to obtain high-resolution image withoutincreasing the physical number of pixels on the CCD 31. Since the otherconfigurations and operations are the same as those according to thethird embodiment, duplicated description is omitted.

The above-mentioned fifth embodiment may also be configured by utilizinga personal computer or the like together with software programs as theabove-mentioned first embodiment is modified into the second embodiment,as in a sixth embodiment of the present invention. FIG. 17 shows a blockdiagram of this sixth embodiment of the present invention. This blockconfiguration is the same as that of the fourth embodiment shown in FIG.13 except that the piezoelectric device drive circuit 33 is controlledby the above-mentioned CCD camera driver 1081. All thefunctions/operations of the sixth embodiment are the same as those ofthe fifth embodiment, and duplicated description is omitted.

A seventh embodiment of the present invention will now be described.FIGS. 18 and 19 illustrate an internal configuration of aprojection-type display device in the seventh embodiment of the presentinvention. As shown in the figures, a plurality of CCD cameras 7 (foursets in the configuration shown in FIG. 18) are provided. The writingfield 1 is divided into four areas A, B, C and D, as shown in FIG. 20corresponding to the respective photography areas of the CCD cameras 7A,7B, 7C and 7D. Thereby, as a result of the CCD cameras 7A through 7Dphotographing the respective areas A through D, and the thus-obtainedphotographed images being combined by the processing control part 8, itis possible to take a photograph at high resolution. Thereby, theuser-drawn image at high resolution can be obtained.

Generally, the resolution of an image is determined by a mutualrelationship between the photography area and number of pixels of a CCDcamera used. That is, when photographing a same area, resolution becomeshigher as the area photographed is smaller. According to the seventhembodiment, since the above-mentioned writing field 1 is divided intothe four areas, and the respective areas are photographed simultaneouslyby the four CCD cameras, the resolution of an image taken by each CCDcamera can be made higher accordingly.

Further, according to the seventh embodiment, whether or not such adividing photography manner is applied may be preferably determined by auser according to an intention of the user and/or an image formed on thewriting field 1. Thereby, when the user-drawn image is relatively simpleone, and, or when the user does not wish such a dividing photography wayfor some reasons, the dividing photography manner may not be applied,and a normal photography such that merely the full area or apredetermined area of the writing field 1 is photographed by the singleCCD camera 7.

Furthermore, more preferably in terms of functions, the number ofdivision in case of the dividing photography may be determined by auser. Instructions as to whether or not the dividing photography mode isselected, and the number of division therein may be input through theswitches 11. According to the seventh embodiment, operativity andfunctionality are improved.

Operation of the processing control part 8 according to the seventhembodiment will now be described with reference to FIG. 21. Theprocessing control part 8 drives the stepper motor 22 (in a step S402)so that the light-blocking plate 21 be inserted when a signal is inputfrom the switch 11 (Yes of in a step S401). Then, after the light beamemitted from the projector 4 is thus blocked, the processing controlpart 8 determines whether instructions for the dividing photography havebeen input from the switches 11 (in a step S403). Preferably, asmentioned above, which one of the dividing photography areas isphotographed, how many divisions the photography area is divided, and soforth may be input at the same time by the user.

When instructions for the dividing photography have not been input inthe step S403 (No in the step S403), the processing control part 8 sendsinstructions to the CCD camera of the CCD cameras 7A through 7D whichcan photograph the entire area of the writing field 1 (for example, aconfiguration is made such that the CCD camera 7A can do so) (in a stepS404), and acquires the photographed image therethrough (in a stepS405).

On the other hand, when instructions for the dividing photography havebeen input in the step S403 (Yes in the step S403), the processingcontrol part 8 sends instructions to CCD cameras (any ones of those 7Athrough 7D) corresponding to the number of photography area divisions,specific photography areas, and so forth according to the instructions(Step S406), and acquires all the photographed images thus taken (in astep S407).

Further, the processing control part 8 combines these photographedimages acquired according to a predetermined arrangement of thephotography areas on the CCD cameras 7, and thus produces one combinedphotographed image (in a step S408).

Then, the processing control part 8 produces the user-drawn image orcombined image according to processing shown in FIG. 6 from the combinedimage acquired in the step S408 (in a step S409). Then, the user-drawnimage or combined image thus generated is stored as mentioned above inthe storage part 10, or is output to the external apparatus from theinput-and-output part 9.

Then, after acquiring the photographed image in the step S405 or S407,the processing control part 8 drives the stepper motor 22 so that thelight-blocking plate 21 may be removed (in a step S410).

In addition, the user-drawn image or the combined image generated isstored as mentioned above in the storage part 10, or is output to theexternal apparatus from the input-and-output part 9.

Thereby, all or a part of the user-drawn image is acquirable in theresolution suitable for the demand of the user. Since the otherconfigurations and operations are the same as those of the thirdembodiment, duplicated description is omitted.

The above-mentioned seventh embodiment may also be configured byutilizing a personal computer or the like together with softwareprograms as the above-mentioned first embodiment is modified into thesecond embodiment. However, in this case, the CCD driver 1081 in thepersonal computer 108 is configured such that the driving control of theplurality of CCD cameras (7A through 7D) can be carried out thereby.

An eighth embodiment of the present invention will now be described.FIGS. 22 and 23 illustrate an internal configuration of aprojection-type display device in the eighth embodiment of the presentinvention.

In the eighth embodiment, a photography part 51 having pan/tiltfunctions performs photography on the writing field 1. FIG. 24 shows aperspective view of the photography part 51. The photography part 51 hasa CCD camera 7 and a shaking mechanism the 52, and can control thephotography area of the CCD camera 7 through the shaking mechanism 52together with a well-known zoom function of the CCD camera 7.

A user may give instructions to the projection-type display device toindicate a desired part of the writing field 1 by operating thephotography part 51 using some of the switches 11. At this time, theprojector 4 displays a currently set photography area of the CCD camera7 on the transparent screen 6, as shown in FIG. 22. Thereby, the usercan control the photography area with checking the actually set areasimultaneously.

FIG. 25 is a block diagram showing a configuration of theprojection-type display device in the eighth embodiment. Differentpoints of the projection-type display device from the projection-typedisplay device in the above-mentioned fifth embodiment are that theshaking mechanism 52 is used instead of the piezoelectric device drivecircuit 33, and also, a fluorescent light 53 for front lighting isadded.

Based on user' instructions from the switches 11, the processing controlpart 8 performs control of the photography part 51. Further, in casehigh resolution photography is performed, the shaking mechanism 52 maybe used. Namely, the writing field 1 is divided and photographed by apart-by-part manner, the thus-obtained partial photographed images arecombined/collected/joined so that a high-resolution photography image isobtained. This dividing photography is achieved by appropriatelycontrolling the optical axis of the CCD camera 7 through theabove-mentioned tilt and pan functions of the shaking mechanism 52. Theuser can select either the dividing photography mode or the normal modein which a photography image is obtained through a single photographyoperation without dividing the writing field 1, by using the switches11. Further, the user may also select the number of divisions of thewriting field 1 in the case of dividing photography mode, also throughthe switches 11.

The dividing photography is achieved by using the plurality of CCDcameras 7A through 7D according to the above-mentioned seventhembodiment, which needs costs for the number of CCD cameras. In contrastthereto, according to the eighth embodiment, only the single CCD camera7 does the same through changing the optical axis thereof appropriately,which thus needs less costs. Thus, according to the eighth embodiment,the projection-type display device excellent in operativity andfunctionality can be provided at low costs.

Furthermore, this projection-type display device in the eighthembodiment is configured such that a storage area in the storage part 10may be determined according to the angle of the CCD camera 7 inconnection with the operation of the shaking mechanism 52.

Further, since the other configurations and operations are the same asthose of the seventh embodiment, duplicated description is omitted.

A ninth embodiment of the present invention will now be descried. FIG.26 illustrates the projection-type display device in the ninthembodiment. An image on the writing field 1 is photographed by the CCDcamera 7 provided inside of the projection-type display device.Therefore, the image on the writing field 1 can be photographed moreeffectively in a condition in which the image is illuminated from theuser side or outside. That is, as shown in the figure, according to thepresent embodiment, a lighting 54 illuminates the writing field from theuser side (outside of the projection-type display device).

Thereby, since the writing field 1 is illuminated from the side oppositeto the projector 4, the efficiency of lighting is improved, and aphotographed image becomes brighter. However, if the light from thelighting 54 is irradiated directly to the user, the user's visibilitymay be degraded accordingly. Then, in this embodiment, a lampshade 55 isprovided such that the light from the lighting 54 may be prevented fromdirectly irradiating the user. The other configurations and operationsof the ninth embodiment are the same as those of the first embodiment,and duplicated description is omitted.

A tenth embodiment of the present invention will now be described. FIGS.27A and 27B illustrate an inside configuration of a projection-typedisplay device in the ninth embodiment. FIG. 27A illustrates a lightbeam 41 emitted from the projector 4, while FIG. 27B illustrates a lightbeam 42 emitted from a lighting 54. If some obstacle were present alongthe path of the light beam 41 from the projector 4 toward thetransparent screen 6, an image of the obstacle would be displayed on thetransparent screen 6 which would be then photographed by the CCD camera7 problematically.

Therefore, it is necessary to locate the lighting 54 out of the path ofthe light beam 41 from the projector 4 toward the transparent screen 6.Thus, since the lighting 55 illuminating the writing field 1 from theside of the projector 4 is located out of the path of the light beam 41from the projector 4 according to the present embodiment, it does nothave a bad influence on the projection image from the projector 4, and,also, the entire display device can be made smaller.

However, if the light from the lighting 54 irradiated directly the CCDcamera 7, a photographed image taken by the CCD camera 7 would fadewhite. Then, according to the tenth embodiment, a lampshade 55 isprovided in such a manner that the light from the lighting 54 may notdirectly irradiate the CCD camera 7.

The other configurations and operations of the tenth embodiment are sameas those of the first embodiment, the duplicated description is omitted.

An eleventh embodiment of the present invention will now be described.FIGS. 28A and 28B illustrate an inside configuration of aprojection-type display device in the eleventh embodiment. FIG. 28Aillustrates respective light beams 42 from lightings 56 and 57, whileFIG. 28B illustrates the light beam 41 from the projector 4.

The writing field 1 should be illuminated brightly as much as possible,and also, the illumination should be made uniformly. Therefore,according to the eleventh embodiment, the lightings 56 and 57 areprovided in symmetrical positions with respect to an axis 58corresponding to the optical axis of the projector 4, thereby thehomogeneity in brightness on the writing field 1 being improvedeffectively.

Thus, according to the eleventh embodiment, since on the side of theprojector 4, the lightings 56 and 57 are provided for illuminating thewriting field 1 approximately symmetrically with respect to the axis 58corresponding to the optical axis of the projector 4, it does not have abad influence on a projection image from the projector 4, brightnessthereon becomes uniform, and the unevenness on the image is eliminated.

However, if the light from the lightings 56 and 57 irradiated directlythe CCD camera 7, a photographed image taken by the CCD camera 7 wouldfade white accordingly. Then, according to the eleventh embodiment,lampshades 55 are provided such that the light from the lightings 56 and57 may not directly irradiate the CCD camera 7.

The other configurations and operations are same as those of the firstembodiment, and duplicated description is omitted.

A twelfth embodiment of the present invention will now be described.FIG. 29 illustrates an internal configuration of a projection-typedisplay device in the twelfth embodiment. As in a common screen used foran OHP, the color of the transparent screen 6 is gray. Accordingly,without particularly illuminating it, it is hard to clearly view animage drawn thereon. That is, when using the transparent screen 6 as awhiteboard, such a problem may occur. Then, according to the twelfthembodiment, an opaque white dispersion sheet 23 may be inserted betweenthe writing field 1 and transparent screen 6.

When using the projection-type display device as a simple displaydevice, the dispersion sheet 23 may be removed to a position such thatit may not be obstructive by a winding mechanism. That is, thedispersion sheet 23 can be removed/inserted through pulling members 25and a winding roller 24, as shown in the figure. It is noted that, inthis embodiment, a configuration is made such that the writing field 1and transparent screen 6 are pressed onto one another forcibly.Therefore, while being pressed by both of the writing field 1 andtransparent screen 6, the dispersion sheet 23 is pulled out/inserted inby the pulling members 25/winding roller 24. Thereby, the dispersionsheet 23 is prevented from twisting or bending between the writing field1 and transparent screen 6, but can be maintained in a plane state.

FIG. 30 illustrates an example of configuration of the above-mentioneddispersion sheet 23, puling members 25 and winding roller 25 togetherwith a winding crank handle 61. As shown in the figure, the pullingmembers (ropes) 25 are provided at both ends of the dispersion sheet 23,and thereby, the dispersion sheet 23 can be pulled withoutright-and-left unbalance in pulling force. Further, the rotation shaftof the winding roller 24 is connected with the winding crank handle 61provided outside of the projection-type display device. Thereby, thewinding roller 24 can pull the dispersion sheet 23 withoutright-and-left unbalance.

According to the twelfth embodiment, the opaque white dispersion sheet23 is provided on the rear side of the writing field 1 with respect tothe user. Thus, the writing field 1 can also be used as a whiteboardsatisfactorily, and thus, a usage scope of the projection-type displaydevice can be effectively widened.

Since the other configurations and operations of the twelfth embodimentare the same as those of the first embodiment, duplicated description isomitted.

A thirteenth embodiment of the present invention will now be described.FIG. 31 illustrates an inner configuration of a projection-type displaydevice in the thirteenth embodiment. This projection-type display devicealso includes an opaque white dispersion sheet 23 which may be insertedbetween the writing field 1 and transparent screen 6 in a state suchthat the dispersion sheet 23 is pressed from both of the writing field 1and transparent screen 6.

FIGS. 312A, 32B and 32C illustrate a configuration of the dispersionsheet 23 in the thirteenth embodiment together with winding rollers 24and a winding crank handle 61. The dispersion sheet 23 includes asufficiently transparent area 62 as shown in FIG. 32C to make an imageprojected on the transparent screen 6 visible by the user presentoutside of the display device. The transparent area 62 has asufficiently large area such that a predetermined image projected by theprojector 4 can be satisfactorily seen from the user. Further, theopaque white area of the diffusion sheet 23 other than theabove-mentioned transparent area 62 also has a sufficiently large areasuch as to be able to cover the entire writing field 1, as shown in FIG.32A.

Further, the dispersion sheet 23 (transparent area 62 is includedtherein) has top and bottom portions thereof wound by the rollingrollers 24, respectively, and can be moved arbitrarily through a windingcrank handle 61 connected with the lower winding roller 24, as shown inthe figures. That is, the winding crank handle 61 provided outside ofthe display device is connected with a rotation shaft of the lowerwinding roller 24, as in the above-mentioned twelfth embodiment.Furthermore, the upper and lower rolling rollers 24 are connected by atiming belt together such that these rollers rotate in synchronizationwith one another in the same direction. Thereby, the dispersion sheet 23is rolled without right-and-left unbalance, and it becomes possible tomove the transparent area 62 up and down arbitrarily. In addition, theabove-mentioned transparent area 62 is thus movable upward or downwardso that this area 62 may not overlap the writing field 1 at all, asshown in FIG. 32A.

According to the thirteenth embodiment, the opaque white dispersionsheet 23 can be inserted on the rear surface of the writing field 1 withrespect to the position of the user as mentioned above, and thus, thisdisplay device can be satisfactorily used as a whiteboard and thus, theusage scope of the projection-type display device can be effectivelywidened.

Since the other configurations and operations are the same as those ofthe first embodiment, duplicated description is omitted.

A fourteenth embodiment of the present invention will now be described.According to any of the above-mentioned embodiments, in case the writingfield 1 does not have a sufficiently structural strength such as tomaintain the plane state during a drawing/writing operation performed bya user thereon with the pen 2 as shown in FIG. 1, an additional supportboard may be provided between the writing field 1 and transparent screen6 or on the side of the transparent screen 6 opposite to the side of thewriting field 1, for reinforcing the writing field 1, according to thefourteenth embodiment.

FIGS. 33A and 33B illustrate the above-mentioned examples of the supportboard 63 according to the fourteenth embodiment, together with thewriting field 1 and transparent screen 6. In FIG. 33A, the support board63 is provided between the writing field 1 and transparent screen 6,while, in FIG. 33B, the support board 63 is provided on the transparentsheet 6 opposite to the writing field 1. In each configuration, thesupport board 63 may be made of is a material having a sufficientstructural strength to bear a force applied by a user in drawing animage on the writing field 1 by the pen 2 and a sufficient transparency,such as acrylic plate, a glass plate, etc. Further, in thisconfiguration, when using a dispersion sheet 23 as provided in theabove-mentioned twelfth or thirteenth embodiment, the dispersion sheet23 may be preferably provided on the writing field 1 opposite to theuser side.

However, it is also possible that, as shown in FIG. 33C, the writingfield 1 and transparent screen 6 are made of a common member (referredto as a writing-field transparent screen 64), in each of theabove-mentioned embodiments. In such a case, as shown in FIG. 33C, it ispreferable that a support board 63 is provided on the surface of thewriting-field transparent screen 64 opposite to the user side, and,also, a dispersion sheet 23 can be inserted therebetween.

Since the other configurations and operations are the same as those ofthe first embodiment, duplicated description is omitted.

Further, the present invention is not limited to the above-describedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

The present application is based on Japanese priority applications. Nos.2001-059321 and 2001-255119, filed on Mar. 2, 2001 and Aug. 24, 2001,respectively, the entire contents of which are hereby incorporated byreference.

1. A projection-type display device comprising: a projection part; aprojection screen allowing an image from said projection part totransmit therethrough to display the same; a writing sheet on whichwriting is carried out by using ink, and distinctly formed from theprojection screen; a photography part photographing a written imagewritten on said writing sheet by using the ink, wherein: saidphotography part takes a picture of an image written on the writingsheet from an opposite side of the writing sheet than on which the imageis written; and said writing sheet is in contact with one surface ofsaid projection screen.
 2. The projection-type display device as claimedin claim 1, wherein: said ink comprises alcohol.
 3. The projection-typedisplay device as claimed in claim 2, wherein: said writing sheet islocated on the same side as that on which a user who draws an image ontosaid writing sheet exists; and said display device further comprises anextracting part extracting a user-drawn image from an image photographedby said photography part.
 4. The projection-type display device asclaimed in claim 3, further comprising a combining part combining atleast a part of the projection image projected onto said projectionscreen with the user-drawn image extracted by said extracting part. 5.The projection-type display device as claimed in claim 1, wherein theoptical axis of said photography part is perpendicular to said writingsheet.
 6. The projection-type display device as claimed in claim 1,further comprising a part making a correspondence between the projectionimage and drawn image.
 7. The projection-type display device as claimedin claim 1, further comprising: an input part inputting the projectionimage externally; a recording part recording at least one of theprojection image, user-drawn image and combined image; and an outputpart outputting the user-drawn image externally.
 8. The projection-typedisplay device as claimed in claim 1, further comprising a blocking partblocking a light beam emitted from a projecting part projecting thelight beam onto said projection screen so as to display the projectionimage thereon.
 9. The projection-type display device as claimed in claim1, wherein: said writing sheet is divided into a plurality of areas;said photography part takes a plurality of photographs of respectiveones of the plurality of areas; and a combining part is provided, and,thereby, a thus-obtained plurality of photographed images are combined.10. The projection-type display device as claimed in claim 9, furthercomprising an input part through which instructions of at least one ofwhether or not a dividing photography is performed in which a part orall of said writing sheet is divided and each division is photographed,and the number of divisions in the dividing photography, are input. 11.The projection-type display device as claimed in claim 1, wherein: amoving part moving a photography area of said photography part on saidwriting sheet is provided; said photography part takes a photographplural times in a manner such that the photography area thereof eachtime corresponds to a different division of said writing sheet; and acombining part is provided, and, thereby, photographed images obtainedthrough the plural times of photography are combined.
 12. Theprojection-type display device as claimed in claim 11, furthercomprising a part displaying the photography area onto said projectionscreen.
 13. The projection-type display device as claimed in claim 11,further comprising an input part through which instructions of at leastone of whether or not a dividing photography is performed in which apart or all of said writing sheet is divided and each division isphotographed, and the number of divisions in the dividing photography,are input.
 14. The projection-type display device as claimed in claim 1,further comprising a lighting part illuminating said writing sheet froma side opposite to a side on which said photography part is provided.15. The projection-type display device as claimed in claim 1, furthercomprising at least one lighting part illuminating said writing sheetfrom the first side on which said photography part is provided.
 16. Theprojection-type display device as clamed in claim 1, further comprisinga dispersion surface removably provided on a surface of said writingsheet opposite to a user who draws an image on said writing surface. 17.The projection-type display device as claimed in claim 1, furthercomprising: a dispersion sheet comprising a dispersion area which coversall or a part of said writing part and a transparent area whichtransmits, to said writing sheet at least a part of a light beam emittedby a part which projects the projection image onto said projectionscreen; and a moving part moving said dispersion sheet.
 18. Theprojection-type display device as claimed in claim 1, operating based oninstructions from a computer via a communication network.